Conventionally, E-cores used on a magnetic assembly are held together with tape or glue. The E-cores must be held in place during assembly until the tape is secured or until the glue is dried. Adding tape or glue to restrain the E-cores requires additional steps during an assembly process and adds cost to the manufacturing process. Accordingly, a need exists for a low-cost bobbin and core assembly method for E-cores that does not require taping or gluing the cores together.